A runway incursion at Rome-Ciampino (CIA), Italy caused a potentialy dangerous situation on August 31, according to infromation from the Italian Air Safety Board (ANSV). A Let 410 (OK-WDT) taxied onto the active runway 15 at intersection AC, although controllers had told the flight to hold short. Controllers instructed an Airbus A.300 on finals to go around. (ANSV)